Donald Trump has deleted some of the Twitter tirade he posted following President Barack Obama's re-election, and added new critiques of NBC's Brian Williams.

Trump began tweeting before the election was called that it was "a total sham and a travesty." After news outlets projected that Obama won the election, Trump tweeted, "Well, back to the drawing board!" He posted more than 10 angry tweets, declaring "our nation is a once great nation divided" and "the world is laughing at us." He encouraged a "revolution in this country."

"The electoral college is a disaster for a democracy," fumed the celebrity mogul.

Williams showed some of Trump's tweets on air, saying he had "driven well past the last exit to relevance and veered into something closer to irresponsible."

Trump tweeted a retort on Wednesday saying Williams "knows that I think his newscast has become totally boring so he took a shot at me last night." He added, "Wouldn't you love to have my ratings?"

He also deleted some of Tuesday night's tirade, including tweets calling for revolution and incorrectly saying that Obama had lost the popular vote. In a new tweet Wednesday, he said the election was "the Republicans to win" but that Republican Mitt Romney hadn't connected with voters.

Trump endorsed Romney in the presidential race and garnered publicity last year for questioning whether Obama was born in the US and eligible to be president.

The Celebrity Apprentice star recently promised to contribute US$5 million to a charity of Obama's choice if the president released his college and passport records.